# Edit history lost on migration

According to a comment, @Marco's answer to Notation about n choose k permutations was edited before migration. However, nothing displays in the edit history. (This seems appropriate to ask here since the original post, and the edit, happened on MO, but I have no objection to migrating to MMSE if that's more appropriate.)

• I will add that the edit is shown in the revision history of the MO answer. Sep 25, 2022 at 9:53
• @MartinSleziak, thanks! Not that you were saying it didn't (or that it did, for that matter), but I still think that this constitutes a bug: there is no indication at all at MSE that the answer on MSE over one user's name was actually edited by another user. In fact, if it weren't for your link, I wouldn't even know how to find the MO answer's revision history, since the answer itself seems no longer to exist. How did you? Sep 25, 2022 at 10:22
• @TheAmplitwist, thanks! Unless I am misunderstanding, this is slightly different: the revision history shows no revisions, rather than linking to the revision history of the MO answer. Maybe this is a special case when the answer has not been edited since migration, so that there is no ‘automatic’ link to the revision history on MSE? Sep 25, 2022 at 10:29
• @LSpice If you view the revision history of Marco's migrated answer on Math SE, then you will see this notice in a grey bar: "Post Migrated Here from mathoverflow.net (revisions)". The first link points to the original answer on MO, and the second link is supposed to point to the revision history of the original answer on MathOverflow. However, you'll notice that it mistakenly links to the revision history of the MO question. Sep 25, 2022 at 11:29
• But it is by design that only the latest revision is migrated: see Does a migration remove edits from the edit history? on Meta SE. Sep 25, 2022 at 11:30
• @TheAmplitwist, thanks! I completely missed that top text. So that (the mis-pointed link) does seem to be a bug, not by design, and I think should be reported. Would you like to do so (or perhaps you have already), or shall I? Sep 25, 2022 at 11:33
• @LSpice That the second link is mis-pointed is the content of the bug report I linked in my very first comment :) Sep 25, 2022 at 11:33
• @TheAmplitwist, sigh, yes, not enough sleep for me, I guess! Thanks! Sep 25, 2022 at 11:34
• No problem! I have to agree that it's not quite clear in the first place (a) that only the latest revision is migrated; (b) how one can access earlier revisions of a migrated post; (c) that there is a bug that causes different behaviour when accessing revisions of migrated questions vs. answers. If you wish, I can write up an answer to this question, summarising our discussion in these comments. Sep 25, 2022 at 11:36
• @TheAmplitwist, as you point it's in some sense a duplicate, but apparently not on MMO, so, sure, if you write up that answer, then I will be pleased to accept it. Sep 25, 2022 at 11:37
• @LSpice Done. I can remove my comments from under your question now, if you'd like. Sep 25, 2022 at 12:22

When a thread is migrated from one site to another, only the latest revision of each post in the thread is moved over. To find the original revisions of a post on a migrated thread, you can do the following:

1. Go to the timeline for the migrated post.
2. Find the entry for the migration notice.
3. Click on the link over the text "revisions" under the "comment" column.

However, unfortunately there is a bug due to which step 3 fails for migrated answers (but works fine for migrated questions). If you do click on the "revisions" link in this case, you'll find that it takes you to https://mathoverflow.net/posts/431135/revisions. But, this is the revisions list of the question migrated from MathOverflow.

So, to find the revisions list of the answer, you need to find the post ID of the answer on MathOverflow, and use that in the above URL. To find the post ID of the answer, click on the link on "mathoverflow.net" in the same timeline entry, which takes you to https://mathoverflow.net/questions/431135/notation-about-n-choose-k-permutations/431157?noredirect=1#431157. This points to the answer migrated from MathOverflow, and so its post ID is 431157.

So, the revisions history of this answer can be found at https://mathoverflow.net/posts/431157/revisions.